This invention pertains to devices for pulling boards or similar work pieces through table saws or the like, and more particularly to such a device which is readily attached to the table of the saw or other tool and which is also readily movable out of the path of the board, if desired.
Powered saws and planes for woodworking are frequently mounted on tables across which a board may be pushed through the tool. Such woodworking machines are generally rapidly rotating devices which tend to resist movement of boards through the blades. Therefore, it is necessary to feed the board continuously through the tool.
A number of problems arise from the operation of such a tool. If the feed is too slow, the tool may create enough frictional heat to cause a discoloration of the board at the cut surface. If the board is hand fed, there is a very present danger of a hand slipping or otherwise getting too close to the blade, with resultant severe injury to the hand. If multiple pieces are being cut, constant attention to the piece being worked on is necessary so that it is only after one piece is finished that the next one can be picked up and placed in position. And occasionally, a board or something embedded in the board will be struck by the tool with such force that the piece will be kicked back with possibly severe injuries to an operator who may be standing behind the board.
Various means have been proposed to alleviate these problems. Extra care on the part of the operator including the use of "pushers" for the boards will reduce some of the danger, but that care must be constant with no lapses. Various devices have been proposed to provide a power-assisted feed of boards through the tool. Nearly all of these have been permanently built into the machine so that if the tool was used, the feed was also operated by the same powered device. This sort of solution works well for production equipment where the cut is always in one direction--usually rip-sawing or planing with the grain. However, where a saw is to be used to rip several pieces and then is later to be used to cross cut a few, the pulling device tends to be clumsily in the way, particularly during a cross-out operation.
Many of the devices, particularly the older ones, require that the board be held down manually to create enough friction against a pulling roller to pull the board. That again required that hands be too close to a fast rotating tool with resultant dangers.
By my invention, I provide a device which can be easily moved from a position in which it is used to an out-of-use position. The friction against the pulling roller is created by another spring loaded roller so that there is no increase in sliding friction between the board and the table surface. And the force between the rollers is readily adjustable because of the use of a unique spring loading.